Water Changes Question-Calcium Decreasing With Water Changes

[SeaHorseQueen]

Hey Everyone! I hope you're have a great start to the weekend. I tested my water parameters today and trying to figure out why calcium is low after every water change.

Tank will be 3yrs old in May.
20g H
Corals: 1 hammer and 1 Sunny D Zoa (bought last night)
Clean Up Crew: 6 Dwarf Hermit Crabs, 1 Bumble Bee Snail, 1 Turbo Snail
Fish: 1 clownfish, 1 juvenile yellow watchman goby

*NOTES*​

4 days ago:

Salinity: 1.027
KH: 8.3
Calcium: 500
NO3: Na
PO4: Na

25% water change after checking parameters

48hrs Ago Parameters:

Calcium: 440
Kh: 8.9
NO3: 39.2
PO4: 0.39
Salinity: 1.026

15% Water change due to NO3 and PO4 being too high. I had peppermint shrimp who wouldn't leave the hammer alone so I traded them in last night and picked up a nice Sunny D Zoa. I have a new light coming so it should be fine until it comes. Since I don't have to feed 3x a day, they should come back down with the help of Seachem Phosguard.

Today's Parameters:

Salinity: 1.026
KH/ALK: 10.0 (0.35ml on syringe so between 9.9-10.2)
NO3: 44.2
PO4: 0.37

What might be going on with the calcium levels? I have like 20-30 mixed sized shells in there for the crabs so I would have thought that would keep it higher. I rinse all my tubes and syringes with rodi water and store the cuvets with rodi in them to keep them clean.

Checkers:

Hanna NO3 & PO4
Salifert KH & Calcium
Refractometer is from Petco that I've had for several years (I calibrate it every time now with Brightwell to 35ppm as instructed)

Salt has stayed the same: Fritz RPM Reef Pro Premium (Blue Box)

I make RODI Water at home now. I make sure the TDS is 0 before collecting the water officially. I've gotten probably 30g of clean water with maybe 50g of waste water.

I had noticed the calcium going all over the place but it didn't hit me that there was something wrong until it was low today because it was staying the in the higher range. With water changes every other day to battle nutrients, due to shrimp's consumption, should I go ahead and do another water change or leave it and see if it needs more time to balance out? It's not a huge tank by any means and it should be balanced out today.

 

[Tahoe61]

Those values for Calcium are not low.
Fritz RPM mixes at 400-430.
The Shrimp presence should have negligible effect on the Calicum levels.
You can proceed with further WC if that's the method you're using to decrease Phosphate and Nitrate.

:)

 

[SeaHorseQueen]

Those values for Calcium are not low.
Fritz RPM mixes at 400-430.
The Shrimp presence should have negligible effect on the Calicum levels.
You can proceed with further WC if that's the method you're using to decrease Phosphate and Nitrate.

:)

Yes, that’s what I’ve been using to decrease the po4 and no3. I had the store check the calcium and alk. All ended up at 7.7 and calcium was 400. So, I’ll have to redo the alk and see why I got such a high number. Maybe I didn’t shake the small bottle hard enough or something.

 

[Tahoe61]

The salt you're using mixes at 8-9 dkh. It may just be a testing error. Over all the values you posted wouldn't concern me. Phosguard is a good intervention. I would use less than the recommended dose, and slowly bring down the Phosphate.

:)